<!DOCTYPE html>

<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>表格</title>
        <style type="text/css">
            .tab {
                border: 1px solid blue ; /* 仅仅设置表格外部边框 */
                margin: auto ;
            }

            .tab tr td {
                border: 1px solid red ; /* 仅仅设置单元格的边框 */
                height: 100px ;
                width: 200px ;
            }
        </style>
    </head>
    <body>

       <table class="tab">
           <tr>
               <td align="left" valign="center">11</td>
               <td align="right" valign="top">12</td>
               <td align="right" valign="bottom">13</td>
               <td align="center" valign="middle">14</td>
           </tr>

           <tr>
               <td></td>
               <td></td>
               <td></td>
               <td></td>
           </tr>

           <tr>
               <td></td>
               <td></td>
               <td></td>
               <td></td>
           </tr>

       </table>

    </body>
</html>